Disk drive apparatus having an improved spindle motor loading mechanism

ABSTRACT

A disk drive apparatus has an eject member that moves in tandem with a disk cartridge from a first position to a second position upon insertion of the disk cartridge into the disk drive apparatus. The eject member has a projection formed thereon. A first spring biases the eject member in a direction opposite the direction of insertion of the removable disk cartridge. A motor ring assembly mounted on a chassis of the apparatus has a rotating member that rotates between an unloaded position and a loaded position. A second spring biases the rotating member toward its loaded position. A spindle motor is mounted in the motor ring assembly. The rotating member has a first cam surface, a second cam surface that extends substantially perpendicularly to the first cam surface, and a lead-in cam angle surface that extends between the first and second cam surfaces at an angle thereto. A shape memory alloy wire or other means is provided to rotate the rotating member from its loaded position toward its unloaded position. As that occurs, the second cam surface of the rotating member moves past the projection on the eject member, thereby allowing the eject member to move back toward its first position under the force of the first spring. This, in turn, allows the projection on the eject member to push against the lead-in cam angle surface of the rotating member to rotate the rotating member further toward its unloaded position.

BACKGROUND

1. Field of the Invention

The present invention relates to disk drives of the type that acceptremovable disk cartridges, and more particularly, to a disk driveapparatus having a mechanism for automatically loading a spindle motor,i.e., moving the spindle motor into engagement with the hub of a diskcartridge upon insertion of the disk cartridge into the drive.

2. Description of the Prior Art

Removable disk cartridges for storing digital electronic informationtypically comprise an outer casing or shell that houses a rotatablerecording medium, or disk, upon which electronic information can bestored. The cartridge shell often comprises upper and lower halves thatare joined together to house the disk. The disk is mounted on a hub thatrotates freely within the cartridge. When the cartridge is inserted intoa disk drive, a motor-driven spindle in the drive must engage the hub inorder to rotate the disk(s) within the cartridge.

Standard floppy disk drives typically employ a mechanism that guides thedisk cartridge as it is inserted into the drive, so that the hub of thedisk is brought downwardly into engagement with a fixed, rotatablespindle. These drives must be of sufficient height to accommodate thevertical movement of the floppy disk. A more preferable solution is toprovide a straight insertion path for the cartridge and to move thespindle motor into engagement with the hub of the cartridge.

The popular and commercially successfully Iomega ZIP™ drive provides astraight insertion path for its disk cartridge. Guide rails within theZIP™ drive guide the cartridge straight into the drive. When thecartridge reaches a certain point during insertion, the front peripheraledge of the cartridge contacts a cartridge receiving stop on a movableplatform within the drive. The spindle motor of the disk drive ismounted on the movable platform. Continued insertion of the cartridgeinto the drive pushes the movable platform backward. As the movableplatform moves backward within the drive, the platform raises to bringthe spindle motor on the platform into engagement with the hub of thedisk cartridge. Additional details of this spindle motor loadingmechanism are provided in co-pending application Ser. No. 08/398,576,entitled "Moveable Internal Platform for a Disk Drive".

Other prior art spindle motor loading mechanisms are described inpublished International Application No. WO 93/18507, U.S. Pat. No.5,317,464 (Witt et al.) and U.S. Pat. No. 4,663,677 (Griffith et al.),the latter of which is assigned to the same Assignee as the presentinvention. All of these references describe removable cartridge diskdrives in which the spindle motor is moved vertically into engagementwith the hub of a disk cartridge upon insertion of the cartridge intothe disk drive. In each case, movement of the spindle motor is effectedthrough a complex series of mechanical linkages. The complexity of suchmechanical linkages increases the manufacturing costs of these diskdrives. Moreover, each of these prior art disk drives requires manualoperation by the user. For example, in both U.S. Pat. No. 4,663,677 andPublished International Application No. WO 93/18507, the spindle motoris brought into engagement with the disk cartridge by the manualoperation of a lever disposed on the front of the drive chassis.Movement of the lever is translated into movement of the spindle motorby a series of linkages, cams and gears. In U.S. Pat. No. 5,317,464, themanual closure of a drive door is translated through a series oflinkages and gears into vertical movement of the spindle motor.

U.S. Pat. No. 4,482,993 discloses a compact disk player that employs amotor driven cam member to move the spindle motor of the drivevertically into engagement with the central hub of a compact disk. Theloading mechanism is not designed for use with disk cartridges of thetype described above. Rather, the disclosed drive is designed to receivestandard compact disks that are not contained within a cartridgehousing. An opto-electronic switch detects insertion of a compact diskinto the drive and activates the motor driven cam member in order tomove the spindle into engagement with the disk hub. As the cam mechanismbrings the spindle motor into engagement with the disk hub, themechanism contacts a mechanical switch that deactivates the cammechanism. Activation of an ejection button causes the motorized cammechanism to be reactivated, thereby lowering the spindle motor.

An improved automatic spindle motor loading mechanism utilizing amotorized ring assembly is described in co-pending application Ser. No.08/438,255, entitled "Disk Drive Having An Automatic Spindle LoadingMechanism." The mechanism described therein is employed in the popularand commercially successful Iomega JAZ™ drive.

High-capacity removable cartridge disk drives, such as the Iomega ZIP™and JAZ™ drives, are becoming increasingly popular with users of desktoppersonal computers and workstations. Both the lomega ZIP™ and JAZ™ diskdrives are presently available in an internal configuration, which canbe installed in the standard drive bay of a desktop personal computer orworkstation, and in an external configuration which can be connected toan external input/output port on a computer. In order to provide thefunctionality of such high-capacity removable cartridge disk drives in alaptop or notebook computer platform, the overall profile of the drivemust be reduced to fit within the low-profile drive bays typically foundon such small computers. Unfortunately, the disk drive apparatus andspindle motor loading mechanisms disclosed in the aforementionedreferences do not provide the reduced profiles necessary for use inlaptop and notebook computers. Additionally, these prior art mechanismsare mechanically complex and increase the cost of drive manufacture.These and other disadvantages make such disk drive apparatus and spindlemotor loading mechanisms impractical for use in low-profile laptop andnotebook computer systems. Accordingly, there is a need for an improveddisk drive apparatus and spindle motor loading mechanism that achieves alow profile and that is simple, cost effective and precise. The presentinvention satisfies this need.

SUMMARY OF THE INVENTION

The present invention is directed to a disk drive apparatus of the typethat receives a removable disk cartridge. According to the presentinvention, the disk drive apparatus comprises an eject member mounted ona chassis of the disk drive apparatus. The eject member moves in tandemwith the disk cartridge from a first position to a second position uponinsertion of the disk cartridge into the disk drive apparatus. The ejectmember has a projection formed thereon. A first spring biases the ejectmember in a direction toward the first position and opposite thedirection of insertion of the removable disk cartridge. In a preferredembodiment, the eject member comprises a slide plate slidably mounted onthe chassis and having an engaging hook that engages a forward end faceof the data cartridge upon insertion of the cartridge into the diskdrive apparatus to cause the slide plate to slide in tandem with thecartridge from the first position to the second position.

A motor ring assembly mounted on the chassis comprises a rotating memberthat rotates between an unloaded position and a loaded position. Aspindle motor is mounted in the motor ring assembly such that rotationof the rotating member from its unloaded position to its loaded positioncauses the spindle motor to translate vertically into engagement with ahub of the removable disk cartridge.

The rotating member has a first cam surface that engages the projectionon the eject member when the eject member is in its first position andthe rotating member is in its unloaded position, to prevent the rotatingmember from rotating toward the loaded position. The rotating memberfurther has a second cam surface that extends substantiallyperpendicular to the first cam surface and that engages the projectionon the eject member when the eject member is in its second position andthe rotating member is in its loaded position, to lock the eject memberin its second position. According to one important feature of thepresent invention, the rotating member further has a lead-in cam anglesurface that extends between the first and second cam surfaces at anangle thereto. A second spring biases the rotating member in a directionof rotation toward its loaded position.

Means are provided for rotating the rotating member from its loadedposition toward its unloaded position against the force of the secondspring such that the second cam surface of the rotating member movespast the projection on the eject member, thereby allowing the ejectmember to move back toward the first position under the force of thefirst spring. This, in turn, allows the projection on the eject memberto push against the lead-in cam angle surface of the rotating member torotate the rotating member further toward its unloaded position. Thus,in accordance with this aspect of the present invention, the lead-in camangle surface of the rotating member serves to reduce the amount ofinitial rotation required to rotate the rotating member to the edge ofthe lead-in cam angle surface. The rotating member need only beinitially rotated to the edge of the lead-in cam angle, at which pointthe force of the projection on the eject member takes over and pushesthe rotating member further toward its unloaded position as the ejectmember springs back to its first position. This is advantageous when themeans by which the initial rotation is effected has limited travel.

According to another feature of the present invention, the means forinitially rotating the rotating member from the loaded position towardthe unloaded position comprises a shape memory alloy wire connectedbetween the chassis and the rotating member. The shape memory alloy wirecontracts upon application of an electrical current thereto to cause therotation.

According to another important feature of the present invention, thespring that biases the rotating member in its loaded position provides aconstant and continual force on the rotating member to maintain therotating member in its loaded position. In this manner, the use of motorring cam slots having plateau regions, such as are typically found inprior art motor ring assemblies, are not needed.

According to yet another feature of the present invention, the slideplate that forms the eject member in the preferred embodiment, has atleast one flexure that has a projection formed thereon. The flexuremoves from a position away from the cartridge, to a position adjacentthe cartridge as the cartridge and slide plate move in tandem uponinsertion of the disk cartridge into the disk drive apparatus. Theprojection on the flexure moves into engagement with a reference hole onthe cartridge as the slide plate and cartridge reach the secondposition, in order to lock the cartridge in place within the disk driveapparatus.

These and other features and advantages of the present invention willbecome evident hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe preferred embodiment, is better understood when read in conjunctionwith the appended drawings. For the purpose of illustrating theinvention, there is shown in the drawings an embodiment that ispresently preferred, it being understood, however, that the invention isnot limited to the specific methods and instrumentalities disclosed. Inthe drawings:

FIG. 1 shows a disk cartridge adapted for use in the disk driveapparatus of the present invention;

FIG. 2 is a bottom view of the disk cartridge of FIG. 1;

FIG. 3 is a bottom view of a disk drive apparatus in accordance with apreferred embodiment of the present invention, showing the diskcartridge of FIG. 1 at an initial stage of insertion therein;

FIG. 4 is a bottom view of the disk drive apparatus of FIG. 3, showingthe disk cartridge at an intermediate stage of insertion therein;

FIG. 5 is a bottom view of the disk drive apparatus of FIG. 3, showingthe disk cartridge fully inserted into the disk drive apparatus;

FIG. 6 is an exploded assembly view of the motor ring assembly of thedisk drive apparatus of FIG. 3;

FIG. 7 is a side view of the motor ring assembly, showing the rotatingmember of the motor ring assembly in an unloaded position;

FIG. 8 is a side view of the motor ring assembly of FIG. 7, showing therotating member of the motor ring assembly in a loaded position;

FIG. 9 is a perspective view of the slide member of the disk driveapparatus of FIG. 3;

FIG. 10 is a perspective view of the chassis of the disk drive apparatusof FIG. 3;

FIGS. 11 and 12 illustrate the movement of the flexures of the slidemember as the slide member moves from a first position, at which thecartridge is not inserted in the disk drive apparatus, to a secondposition in which the cartridge is fully inserted into the disk driveapparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, wherein like numerals indicate like numeralsthroughout, there is shown in FIGS. 1 and 2 an exemplary disk cartridge10 adapted for use in the disk drive apparatus of the present invention.As shown, the disk cartridge 10 comprises an outer casing 12 havingupper and lower shells 22, 24 that mate to form the casing. The frontperipheral edge 20 of the disk cartridge 10 has angled outer edges 20a,20b. Preferably, the upper and lower shells 22, 24 of the outer casing12 are formed of plastic.

A disk-shaped information storage medium (not shown) is affixed to a hub16 that is rotatably mounted in the casing 12. In the presentembodiment, the storage medium comprises a flexible magnetic storagemedium, however, in other embodiments, the disk may comprise a rigidmagnetic disk, a magneto-optical disk or an optical storage medium. Anopening 21 on the bottom shell 24 of the casing 12 provides access tothe disk hub 16. A head access opening 30 in the front peripheral edge20 of the disk cartridge 10 provides access to the surfaces of thestorage medium by the read/write heads of the disk drive apparatus.

A shutter 18 (not shown in FIG. 1) is provided on the front peripheraledge 20 of the disk cartridge 10 to cover the head access opening 30when the cartridge is not in use. When the cartridge is inserted intothe disk drive apparatus, the shutter 18 moves to the side exposing thehead access opening 30 and thereby providing the read/write heads of thedrive with access to the storage medium.

FIGS. 3-5 are bottom views of a disk drive apparatus 40 according to apreferred embodiment of the present invention, showing the diskcartridge 10 in various stages of insertion into the apparatus 40. FIG.3 shows the cartridge at an initial stage of insertion; FIG. 4 shows thecartridge at an intermediate stage of insertion; and FIG. 5 shows thecartridge in a fully inserted position.

According to the present invention, the disk drive apparatus 40comprises a rigid chassis 42 that has a pair of opposing guide rails(130, 132 of FIG. 10) that guide the disk cartridge 10 into theapparatus. A slide plate 44 is slidably mounted on the chassis 42 and iscapable of moving from a first position (FIG. 3--cartridge not inserted)to a second position (FIG. 5--cartridge fully inserted). A first spring66, which is attached at one end to a hook 70 on the chassis and at theother end to a hook 71 on the slide plate, biases the slide plate in adirection toward its first position (FIG. 3).

The slide plate 44 has two legs 76, 78 that extend lengthwise of thedisk drive apparatus. Tabs 80, 82 formed at the proximal ends of thelegs 76, 78 extend through, and ride along, narrow slots 81, 83 in thechassis. The tabs 80, 82 hold the rear of the slide plate 44 on thechassis 42. The other end of the slide plate 44 is slidably held on thechassis by means of two tabs 63, 65 formed on the chassis 42 (see also,FIG. 10), which overlap respective edges of the legs 76, 78 of the slideplate 44.

Each leg 76, 78 of the slide plate 44 has a cartridge engaging hook 84,86 that extends through a cut-out 77, 79 in the chassis 42 to engage arespective angled outer edge 20a, 20b on the forward end face of thedisk cartridge 10. FIG. 3 illustrates the position of the disk cartridgeat a point where the outer edges 20a, 20b initially come into contactwith the respective engaging hooks 84, 86 of the slide plate 44.Referring to FIG. 4, as the disk cartridge 10 is pushed further into thechassis 42 (by the user), the slide plate 44 moves in tandem with thedisk cartridge by means of the engaging hooks 84, 86, against the forceof the first spring 66. The fully inserted position of the diskcartridge 10 and slide plate 44 (i.e., the second position of the slideplate), is illustrated in FIG. 5.

In accordance with the present invention, the slide plate 44 and itsrespective engaging hooks 84, 86 define an eject member for receivingand ejecting the disk cartridge to and from the disk drive apparatus. Inother embodiments, the eject member may take other forms, and thepresent invention is by no means limited to the particular configurationof the eject member described herein.

Further according to the present invention, the disk drive apparatus 40additionally comprises a motor ring assembly 46 that is mounted to thechassis 42, as described hereinafter in greater detail. In the preferredembodiment, the motor ring assembly comprises a stationary member 96(see FIG. 6), which is affixed to the chassis 42, and a rotating member106 that is rotatably mounted on the stationary member 96. The rotatingmember 106 rotates between an unloaded position (FIG. 3) and a loadedposition (FIG. 5). A second spring 68, which is connected at one end toa hook 72 on the chassis and at the other end to a hook 74 on the outercircumference of the rotating member 106, biases the rotating member 106in a direction of rotation toward its loaded position (ie., clockwise inFIG. 3).

The rotating member 106 of the motor ring assembly 46 has a cam member56 extending substantially radially outwardly therefrom. The cam memberhas a first cam surface 58, a second cam surface 62 disposedsubstantially perpendicularly to the first cam surface 58, and a lead-incam angle surface 60 that extends between the first and second camsurfaces 58, 62 at an angle thereto. When no cartridge is inserted inthe disk drive apparatus 40, and the slide plate 44 is therefore in theposition shown in FIG. 3, a projection 64 on the slide plate 44 abutsthe first cam surface 58 of the cam member 60 and prevents the rotatingmember 106 of the motor ring assembly 46 from rotating toward its loadedposition (FIG. 5) under the force of the second spring 68.

Referring next to FIG. 4, as the disk cartridge is inserted into thedisk drive, and the slide plate 44 begins to move toward its secondposition (FIG. 5), the projection 64 on the slide plate 44 moves pastthe edge of the first cam surface 58, onto the lead-in cam angle surface60. As the projection 64 moves along the lead-in cam angle surface 60,the rotating member begins to move (clockwise in FIG. 3) toward itsloaded position under the force of spring 68.

Referring next to FIG. 5, as the slide plate 44 moves into its secondposition 44 (cartridge fully inserted), the projection 64 moves past thelead-in cam angle surface 60, allowing the rotating member 106 to rotateinto its fully loaded position. Thus, in FIG. 5, the disk cartridge isfully inserted, the slide plate has reached its second position, and therotating member 106 of the motor ring assembly 46 is in its fully loadedposition. As described hereinafter in greater detail, rotation of therotating member 106 into its loaded position (FIG. 5) brings a spindlemotor 102 (see, FIG. 6), which is mounted in the motor ring assembly 46,into engagement with the hub 16 of the disk cartridge 10 in order torotate the hub 16 at high speeds. At this point, the projection 64 iscaptured by, and abuts, the second cam surface 62 of the cam member 56,locking the slide plate 44 in place and preventing it from moving backtoward its first position under the force of spring 66.

According to another important feature of the present invention, aportion of the slide plate 44 is cut-out to form long flexures 48, 50having cartridge locating projections 88, 90 formed at their respectiveends. As the slide plate 44 moves in tandem with the disk cartridgetoward the fully inserted position (FIG. 5), the flexures 48, 50 travelalong inclined cam slots (described hereinafter) to drive the cartridgelocating projections 88, 90 through cutouts 52, 54 in the chassis andinto engagement with the reference holes 26, 28 on the cartridge 10. Inthis manner, the reference holes 26, 28 on the cartridge 10 and therespective cartridge locating projections 88, 90 on the slide plate 44are synchronized to come together just as the cartridge reaches itsfully inserted position. In other embodiment, the slide plate 44 mayhave only a single flexure (48 or 50), having a projection that engagesone of the reference holes (26 or 28) on the cartridge 10.

According to another feature of the present invention, a shape memoryalloy wire 92 is attached between the hook 74 on the rotating member anda hook 94 at the rear end of the chassis 42. Shape memory alloy wirescontract like muscles when electrically driven. Due to the resistance ofa shape memory alloy wire, electrical current applied to the wire causesthe temperature of the wire to increase, which, in turn, changes thecrystal structure of the alloy, causing the wire to contract by severalpercent of its length. This phenomenon is referred to as the shapememory phenomenon. The wire is easily stretched back to its originallength after it cools back to room temperature. In the presentembodiment, the shape memory alloy wire 92 is made of nickel-titanium,and is available from Dynalloy, Inc., 18662 MacArthur Blvd., Suite #103,Irvine, Calif. 92715 under the trademark Flexinol™. In the presentembodiment, the Flexinol™ wire is 0.005" in diameter, and, in itsrelaxed state, extends from hook 94 to hook 74 approximately 85 mm, andthen is doubled over and extends back to hook 94 for a total length ofapproximately 170 mm.

Still referring to FIG. 5, in accordance with the present invention,when it is desired to eject the disk cartridge 10 from the disk driveapparatus 40, the shape memory alloy wire 92 is used to initiaterotation of the rotating member 106 back toward its unloaded position(i.e., counter-clockwise in FIG. 5). Shape memory alloy wires, includingthe Flexinol™ wire 92 of the preferred embodiment, provide a limitedamount of shrinkage for practical use. According to an important featureof the present invention, rather than using the shape memory alloy wire92 to completely unload the spindle motor before the cartridge isejected, the lead-in cam angle 60 is used to allow the eject force ofthe slide plate 44 to finish the unloading of the spindle motor.Specifically, when the shape memory alloy wire 92 contracts uponapplication of electrical current thereto (in a conventional manner),the rotating member 106 of the motor ring assembly 46 rotates backtoward its unloaded position (counter-clockwise in FIGS. 3-5), until thesecond cam surface 62 has just moved past the projection 64 on the slideplate 44, and the projection 64 is poised at the edge of the lead-in camangle 60 (FIG. 4). At this point, the spindle motor 102 has becomeunchucked from the hub 16 of the disk cartridge 10, and the projection64 on the slide plate 44 is free of the confines of the second camsurface 62. The slide plate 44 therefore begins to move back toward itsfirst position under the force of the first spring 66. During thismovement, as the projection 64 on the slide plate 44 pushes against thelead-in cam angle surface 60, the rotating member 106 is further rotatedtoward its fully unloaded position. As the slide plate reaches its firstposition, as shown in FIG. 3, the projection 64 moves back onto thefirst cam surface 58 of the cam member 56, at which point the rotatingmember 56 has reached its fully unloaded position and is once again heldin place by the projection 64.

By providing the lead-in cam angle surface 60 between the first andsecond cam surfaces 58, 62, the amount of rotation that must be achievedby contraction of the shape memory alloy wire 92 is reduced; the shapememory alloy wire 92 need only contract enough to rotate the rotatingmember 106 to the edge of the lead-in cam angle 60. Thus, the problem oflimited shrinkage of the shape memory alloy wire 92 is overcome. As canbe appreciated, this aspect of the present invention can be applied toreduce the amount of rotation needed from any driving means, not justthe shape memory alloy wire 92 employed in the present invention. Forexample, any drive mechanism that has limited travel, including, forexample, a small electric motor and/or gear driven assembly, can benefitfrom the provision of the lead-in cam angle surface 60 to reduce theamount of travel that is needed to

In the present embodiment, an electrical current of 250 mA is applied tothe shape memory allow wire 92, in a conventional manner. According to adata sheet supplied with the Flexinol™ wire used in the preferredembodiment, a current of 250 mA results in a maximum pull force of 230gms. Because the Flexinol™ wire (total length approximately 170 mm) isdoubled over between hooks 94 and 74, the 230 gms pull force iseffectively doubled to about 460 gms. Total shrinkage of the shapememory alloy wire 92 during this process is approximately 3.5% of itslength, or approximately 3.0 mm of shrinkage between hooks 94 and 74.

In the present embodiment, the 250 mA current is applied to the shapememory alloy wire 92 for 1 sec., and then the disk drive apparatuschecks to see if the disk cartridge 10 has been successfully ejected. Ifthe cartridge is not yet successfully ejected, the 250 mA current isagain applied to the shape memory alloy wire 92 for 1 sec. Thiscontinues until it is determined that the cartridge has beensuccessfully ejected. Detection of successful cartridge ejection can beperformed in any conventional manner.

FIG. 6 is an exploded perspective view of the motor ring assembly 46,showing further details thereof. In this perspective, the motor ringassembly 46 is viewed from the opposite side as that shown in FIGS. 3-5.FIG. 7 is a side view of the motor ring assembly 46, showing therotating member 106 in its fully unloaded position (FIG. 3). FIG. 8 is aside view of the motor ring assembly 46 showing the rotating member 106in its fully loaded position (FIG. 5).

According to the preferred embodiment, the motor ring assembly 46comprises the stationary member 96 and the rotating member 106, which isrotatably mounted on the stationary member. The stationary member 96 hasa plurality of locating features 100 that mate with corresponding holes126 (see, FIG. 10) in the surface of the chassis 42 to secure thestationary member 96 to the chassis 42. A spindle motor 102, which spinsat high speeds to rotate the hub 16 of the disk cartridge, is, in thepresent embodiment, mounted in the rotating member 106. A flex circuit104 (not shown in other Figures) provides electrical signals to thespindle motor to control its rotation.

In the present embodiment, the stationary member 96 has a plurality ofradially extending cam projections 98, and the rotating member 106 has acorresponding plurality of inclined cam slots 108 into which the camprojections 98 extend when the stationary and rotating members 96, 106are assembled together. FIG. 7 shows the position of the cam projections98 within the cam slots 108, when the rotating member 106 is in itsfully unloaded position. As the rotating member rotates under the forceof spring 68 toward its loaded position, the inclined surfaces of thecam slots 108 move against the respective cam projections 98 on thestationary member, causing the rotating member to translate verticallyand to bring the spindle motor 102 into engagement with the hub 16 ofthe disk cartridge 10. FIG. 8 shows the rotating member in its fullyloaded position.

While in the present embodiment, the cam projections 98 are formed onthe stationary member 96 and the inclined cam slots 108 are formed inthe rotating member 106, this could be reversed. Also, the clockwise andcounter-clockwise rotational directions of the rotating member 106described herein represent a preferred embodiment and are not meant tobe limiting. These directions could be reversed in other embodiments.Furthermore, whereas in the present embodiment, the rotating member 106forms the outer ring of the assembly and the stationary member 96 formsthe inner ring, in other embodiments, this arrangement can be reversed.That is, the inner member can be the one that rotates, while the outermember remains stationary.

According to another important feature of the present invention, unlikeprior art motor ring assemblies in which the cam projections are forcedonto a plateau region of the corresponding cam slots to maintainengagement of the spindle motor and disk hub (which requires substantialadditional rotating force), the cam slots 108 of the motor ring assemblyof the present invention do not include such a plateau region. Rather,engagement of the spindle motor 102 and disk hub 16 in the presentembodiment is maintained by the continual rotating force applied to therotating member 106 by the second spring 68. Thus, whereas in the priorart, the rotational force on the rotating member of a motor ringassembly is removed once the cam slots are forced onto the plateauregion of the corresponding cam slots, the present invention differs inthat a constant and continual force is applied to the rotating member tokeep the spindle motor 102 and disk hub 16 engaged; the cam slots 108 donot include a plateau region.

FIG. 9 is a perspective view of the slide member 44 of the disk driveapparatus of FIGS. 3-5, showing in more detail the various features ofthe slide plate 44 described above, including, for example, thecartridge engaging hooks 84, 86, the mounting tabs 80, 82, hook 71,projection 64, legs 76 and 78, flexures 48 and 50, and cartridgelocating projections 88 and 90. As further shown in FIG. 9, each of theflexures 48, 50 of the slide plate has an upturned tab 110, 112 on whichis formed a respective cam projection 116, 114. As describedhereinafter, the cam projections 114, 116 ride along corresponding camslots on the chassis to move the flexures vertically during cartridgeinsertion and ejection, in accordance with a cartridge locating featureof the present invention.

FIG. 10 is a perspective view of the chassis 42 of the disk driveapparatus, in accordance with a preferred embodiment thereof. FIG. 10shows further details of the various features of the chassis 42described above. As shown, the chassis 42 has cutouts 77 and 79 throughwhich the cartridge engaging hooks 84, 86 of the slide plate 44 extendto engage the angled outer edges 20a, 20b of the front peripheral edgeof the disk cartridge 10. Narrow slots 81 and 83 provide a means forslidably attaching the slide plate 44 to the chassis 42 using tabs 80and 82 on the respective legs 76, 78 of the slide plate 44. Tabs 63, 65overlap respective edges of the legs 76, 78 at the forward end of theslide plate 44 to hold that end of the slide plate 44 on the chassis 42.Cut-outs 52 and 54 are provided, through which the cartridge locatingprojections 88 and 90 move into and out of engagement with therespective reference holes 26 and 28 on the cartridge. Holes 126 areprovided in the chassis to receive the locating features 100 on thestationary member 96 of the motor ring assembly 46. An opening 128 isprovided through which the spindle motor 102 engages the hub 16 of thedisk cartridge. Hooks 70 and 72 are provided for attachment of thesprings 66 and 68, respectively. Hook 94 is provided for attachment ofone end of the shape memory alloy wire 94. Opposing guide rails 130 and132, which are spaced at an interval substantially equal to the width ofthe disk cartridge 10, are provided to guide the disk cartridge 10 intothe chassis. Additionally, upturned tabs 118 and 122 are provided oneach side of the chassis 42 adjacent the respective cutouts 54 and 52.The tabs 118 and 122 each have a respective cam slot 120, 124 extendingtherethrough. The cam slots 120, 124 receive the respective camprojections 114, 116 on the flexures 48, 50 of the slide plate 44, asdescribed hereinafter.

FIGS. 11 and 12 illustrate the cartridge locating feature of the presentinvention. FIG. 11 shows the position of the slide plate 44 and one ofthe flexures 50 when no cartridge is inserted in the disk driveapparatus 40. In this position, the cam projection 114 on the tab 112 ofthe flexure 50 is positioned at the highest point of the cam slot 120 ontab 118 of the chassis. In this position, the flexure 50 is raised fromthe plane of the slide plate such that the cartridge locating projection90 is pulled upwardly (in FIG. 11) away from the opening provided bycut-out 54. Referring now to FIG. 12, as the cartridge 10 (not shown inFIG. 12) is inserted into the disk drive apparatus, the slide plate 44moves toward its second position. As a consequence, the cam projection114 on the flexure 50 moves down the inclined surface of the cam slot120, thereby bringing the flexure back into the plane of the slide plate44 and allowing the cartridge locating projection 90 to extend into andthrough the cut-out 54, where the projection 90 engages thecorresponding reference hole 28 on the bottom of the cartridge 10 (asbest shown in FIG. 5). The opposite flexure 44 undergoes similarmovement. The reference holes 26, 28 on the cartridge 10 and therespective cartridge locating projections 88, 90 on the slide plate 44are synchronized to come together just as the cartridge 10 reaches itsfully inserted position. The cartridge locating projections 88, 90 holdthe cartridge in place in the chassis. When the cartridge is ejected,and the slide plate 44 move back to its first position (FIG. 11), thecam projections 114 and 116 move back up the respective cam slots 120,124, thereby raising the flexures and bringing the cartridge locatingprojections 88, 90 out of engagement with the cartridge reference holes26, 28. In other embodiments, the slide plate 44 may have only oneflexure (48 or 50), having a projection that engages only one of thereference holes (26 or 28) of the disk cartridge 10.

As the foregoing illustrates, the present invention is directed to adisk drive apparatus having an automatic spindle motor loadingmechanism. The various features of the disk drive all contribute to anextremely low-profile, which is advantageous for use in smaller computersystems, such as laptop and notebook computer systems. Additionally, themechanics of the apparatus are simplified and less costly tomanufacture. It is understood that changes may be made to theembodiments described above without departing from the broad inventiveconcepts thereof. Accordingly, the present invention is not limited tothe particular embodiments disclosed, but is intended to cover allmodifications that are within the spirit and scope of the invention asdefined by the appended claims.

What is claimed is:
 1. A disk drive apparatus of the type that receivesa removable disk cartridge, comprising:an eject member mounted on achassis of the disk drive apparatus, said eject member moving in tandemwith said disk cartridge from a first position to a second position uponinsertion of the disk cartridge into the disk drive apparatus, saideject member having a projection formed thereon; a first spring biasingsaid eject member in a direction toward said first position and oppositethe direction of insertion of said removable disk cartridge; a motorring assembly mounted on the chassis and comprising a rotating memberthat rotates between an unloaded position and a loaded position, saidrotating member having a first cam surface that engages said projectionwhen the eject member is in said first position and the rotating memberis in said unloaded position to prevent the rotating member fromrotating toward said loaded position, and said rotating member having asecond cam surface that extends substantially perpendicular to saidfirst cam surface and that engages said projection on said eject memberwhen the eject member is in said second position and the rotating memberis in said loaded position to lock the eject member in said secondposition, said rotating member further having a lead-in cam anglesurface that extends between the first and second cam surfaces at anangle thereto; a second spring biasing the rotating member in adirection of rotation toward said loaded position; a spindle motormounted in said motor ring assembly such that rotation of the rotatingmember from said unloaded position to said loaded position causes thespindle motor to translate vertically into engagement with a hub of saidremovable disk cartridge; and means for rotating said rotating memberfrom said loaded position toward said unloaded position against theforce of said second spring such that said second cam surface of therotating member moves past the projection on said eject member, therebyallowing the eject member to move back toward said first position underthe force of said first spring and allowing the projection on the ejectmember to push against the lead-in cam angle surface of the rotatingmember to rotate the rotating member further toward its unloadedposition.
 2. The disk drive apparatus of claim 1 wherein said means forrotating said rotating member from said loaded position toward saidunloaded position comprises a shape memory alloy wire connected betweensaid chassis and said rotating member, said shape memory alloy wirecontracting upon application of an electrical current thereto to causesaid rotation.
 3. The disk drive apparatus of claim 1 wherein said ejectmember comprises a slide plate slidably mounted on said chassis andhaving an engaging hook that engages a forward end face of said datacartridge upon insertion of the cartridge into the disk drive apparatusto cause said slide plate to slide in tandem with said cartridge fromsaid first position to said second position.
 4. A disk drive apparatusof the type that receives a removable disk cartridge and having a motorring assembly mounted on a chassis of the disk drive apparatus, saidmotor ring assembly comprising:a rotating member that rotates between anunloaded position and a loaded position; a stationary annular member onwhich said rotating member is rotatably mounted; a spring biasing therotating member in a direction of rotation toward said loaded position,said spring providing a continual spring force to maintain said rotatingmember in said loaded position; and a spindle motor mounted in saidmotor ring assembly such that rotation of the rotating member from saidunloaded position to said loaded position causes the spindle motor totranslate vertically into engagement with a hub of said removable diskcartridge, wherein one of said rotating member and said stationarymember having a plurality of cam projections thereon, and the other ofsaid rotating member and said stationary member having a plurality ofcam slots that each engage a respective one of said cam projections,said cam slots having inclined surfaces up which said cam projectionsmove when said rotating member rotates toward the loaded position tocause said rotating member to translate vertically into the loadedposition.
 5. The disk drive apparatus recited in claim 4 furthercomprising a shape memory alloy wire connected between said rotatingmember and said chassis, said shape memory alloy wire contracting uponapplication of an electrical current thereto and causing said rotatingmember to rotate toward said unloaded position against the force of saidspring.
 6. The disk drive apparatus recited in claim 4 wherein theinclined surfaces of said cam slots have a constant slope, and whereinsaid spring provides a continual spring force to maintain said camprojections at a position along said respective inclined surfaces ofsaid cam slots corresponding to the loaded position of said rotatingmember, until a shape memory alloy wire, connected between said rotatingmember and said chassis contracts upon application of electrical currentthereto to move said cam projections from said position corresponding tothe loaded position.
 7. A disk drive apparatus of the type that receivesa removable disk cartridge and having a motor ring assembly mounted on achassis of the disk drive apparatus, said motor ring assemblycomprising:a rotating member that rotates between an unloaded positionand a loaded position; a spring biasing the rotating member in adirection of rotation toward said loaded position; a spindle motormounted in said motor ring assembly such that rotation of the rotatingmember from said unloaded position to said loaded position causes thespindle motor to translate vertically into engagement with a hub of saidremovable disk cartridge; and a shape memory alloy wire connectedbetween said rotating member and said chassis, said shape memory alloywire contracting upon application of an electrical current thereto andcausing said rotating member to rotate toward said unloaded positionagainst the force of said spring.
 8. A disk drive apparatus of the typethat receives a removable disk cartridge, comprising:a slide plateslidably mounted on a chassis of said disk drive apparatus, said slideplate engaging said removable disk cartridge and moving in tandemtherewith from a first position to a second position upon insertion ofthe disk cartridge into the disk drive apparatus, said slide platehaving a cam projection; a first spring biasing said slide plate in adirection toward said first position and opposite the direction ofinsertion of said removable disk cartridge; a motor ring assemblymounted on the chassis and comprising a rotating member that rotatesbetween an unloaded position and a loaded position, said rotating memberhaving a first cam surface that engages the cam projection on said slideplate when the slide plate is in said first position and the rotatingmember is in said unloaded position to prevent the rotating member fromrotating toward said loaded position, and said rotating member having asecond cam surface that engages the cam projection on said slide platewhen the slide plate is in said second position and the rotating memberis in said loaded position to lock the slide plate in said secondposition; a second spring biasing the rotating member in a direction ofrotation toward said loaded position; a spindle motor mounted in saidmotor ring assembly such that rotation of the rotating member from saidunloaded position to said loaded position causes the spindle motor totranslate vertically into engagement with a hub of said removable diskcartridge; and a shape memory alloy wire connected between said rotatingmember and said chassis, said shape memory alloy wire contracting uponapplication of an electrical current thereto and causing said rotatingmember to rotate toward said unloaded position against the force of saidsecond spring such that said second cam surface of the rotating membermoves out of engagement with the cam projection on said slide plate,thereby allowing the slide plate to move back to said first positionunder the force of said first spring.
 9. The disk drive apparatus ofclaim 8 wherein movement of the slide plate from said first position tosaid second position upon insertion of the disk cartridge into said diskdrive apparatus causes the cam projection on the slide plate to movepast the first cam surface of said rotating member, thereby freeing therotating member and allowing the rotating member to rotate under theforce of said second spring from said unloaded position to said loadedposition and causing the second cam surface of the rotating member tomove into engagement with the cam projection on said slide plate to lockthe slide plate in said second position, and wherein thereafter,application of an electrical current to said shape memory alloy wirecauses said rotating member to rotate back toward said unloaded positionsuch that the second cam surface thereof moves past the cam projectionon said slide plate, thereby releasing said slide plate and allowing theslide plate to move back to said first position under the force of saidfirst spring.
 10. The disk drive apparatus of claim 8 wherein saidrotating member further comprises a lead-in cam angle surface extendingbetween said first and second cam surfaces of the rotating member, saidlead-in cam angle surface serving to minimize the amount of rotation ofthe rotating member needed to release the cam projection of said slideplate from engagement with the second cam surface of the rotatingmember, the force of said slide plate acting against said lead-in camangle surface through the cam projection thereof to further rotate saidrotating member back to said unloaded position.
 11. The disk driveapparatus recited in claim 8 wherein said second spring provides aconstant and continual spring force to maintain said rotating member insaid loaded position.